I am working on a project and need to accurately measure the time it takes to do an emergency brake while driving. To keep this simple i would probably need power a LED or a LSD screen to alert the test subject to do an emergency brake.
I will also be using two Load Cells (one for the accelerator pedal and the other for the brake pedal) after doing some research I've decided the FX1901 Load Cell would meet my needs. I will also be using the amplifier INA125 (I considered the HX711 but that only has a sampling frequency of 80 Hz and i need at least 1000 Hz). To measure time I will be using the arduino board for that, will this be accurate enough?
Will one Uno be able to handle all this? or will i need 2 Unos connected (one uno for each load cell) or possibility a mega or another board?
Is there a reason you can't use pressure switches in the brake and accelerator lever footpads.
Using load-cells, which are a low level signal sensors in a noisy automotive environment will possibly pose some interference problems.
Unless you want to measure throttle and brake application pressures.
I should clarify that will would be building a stationary test rig with some pedals (Made in house). my test subjects will be people who have recently gone through leg surgery so measuring force applied on the pedal is required. The time it takes to apply the force is what i am trying to measure. for now i will be using a simple LED light to indicate to the test subject when to start braking, and possibly make the stimulus more believable using some simulation at a later date. Ive seen many academic papers use this method, however with different controllers, id like to do it with an arduino.
I might also use a potentiometer encoder to measure to position of the pedal. but i need to measure the force placed on the pedal. ( I know i can use a calibrated spring and an encoder to measure the force too).
TonyWilk:
Question remains: what will you do with the 1000 * 2 measurements per second ?
Do you need to store the values or transmit them somewhere, or simply time between pre-defined 'trip points' of the measurement values ?
For this i plan to store the data on a memory card and then use a matlab script to do the post processing. (the data captured should be the force reading on the accelerator and brake pedals, time, and when the LED light was flashed)
ideally id like to link the arduino to a laptop and produce the results seamlessly.
Your scenario confuses me. In a vehicle with automatic transmission, you always brake with the left foot, since it's already near the brake pedal. Why the accelerator pedal sensor?
Paul_KD7HB:
In a vehicle with automatic transmission,
So i am testing for a manual car, so the right foot will be on the accelerator and then move to the brake pedal. Placing the sensor on the accelerator will also tell me the thinking time for the patient so i would know at what point they would stop accelerating.
I will be measuring the time it takes for the patient to move the right foot from the accelerator and then apply a force of 300 N on the brake pedal.
I should have a third pedal (Clutch) but that would not need a sensor.
Delta_G:
That's not how I was taught. That's how you end up with old ladies running down the road with one foot on the break and one on the gas. Wearing out break pads for no good reason and wasting gas.
Oh wait, maybe you're in England or something so you're always backwards and you do the gas with the left foot too.
I was not taught that in drivers training, either. 1955 Ford V8, three speed manual. Then a 1956 Fordomatic POS!
I taught the correct method my self. Left foot a short distance from the brake. Right foot on the accelerator. Accident avoidance uses either braking to avoid, or accelerating to avoid.
Learned to heel and toe brake/accelerate in my 1959 AH Sprite.
Paul_KD7HB:
Your scenario confuses me. In a vehicle with automatic transmission, you always brake with the left foot, since it's already near the brake pedal. Why the accelerator pedal sensor?
Paul
Nope, I was taught to use the accelerator foot, right foot. (The same foot no matter what side of the road you drive.)
That way you come off the throttle and onto the brake.
The left foot on the floor or footrest provides some sort of base to work against.
I think its quicker than picking the other foot up off the footrest or floor, and onto the brake.
I like the concept of the rig, and I'd say its doable, building the mechanics of the rig would be out of my league.
A strain gauge on the pedal arms may do the job, you would have to calibrate it.
With a few kg masses you could do it.
Unless you have some load-cells that you can put on the pedal pads.
Tom....
